Elevator-conveyor for bulk material

ABSTRACT

An elevator-conveyor for carrying bulk materials upwards or downwards over a path which extends at least in part vertically or at a slope between two different levels. The conveyor comprises two belts which are pressed against each other at their edges by pneumatic or hydraulic fluid pressure in such a manner that the material is fully enclosed. The pressure fluid acts either in two separate boxes along whose open sides the belts are tightly conducted, or in a single box through which both belts run in common.

Foreign Application Priority Data United States Patent 1 3,762,534 Beresinsky 1 Oct. 2, 1973 I541 ELEVATOR-CONVEYOR FOR BULK 2,978,095 4/1961 Jenike 198/165 MATERIAL 3,603,448 9/1971 Okano 198/162 [75] Inventor: Isaac Beresinsky, Haifa, Israel R N TENTS OR APPUCATlONS Assigneez Moledeth Development p y 547,416 8/1932 Germany 198/165 Ltd., Haifa, Israel Primary ExaminerEdward A. Sroka [22] Ffled: July 1971 Attorney-Eric H. Waters et al.

[57] ABSTRACT An elevator-conveyor for carrying bulk materials upwards or downwards over a path which extends at least in part vertically or at a slope between two different levels. The conveyor comprises two belts which are pressed against each other at their edges by pneumatic or hydraulic fluid pressure in such a manner that the material is fully enclosed. The pressure fluid acts either in two separate boxes along whose open sides the belts are tightly conducted, or in a single box through which both belts run in common.

15 Claims, 12 Drawing Figures Aug. 5, 1970 Israel 35062 52 us. Cl. 198/165 [51] Int. Cl. 865g 15/14 [58} Field of Search 198/165, 184, D16. 2, 198/162;'226/l72 [56] References Cited UNITED STATES PATENTS 2,971,632 2/1961 Sauvee 198/165 1 l{ 4 l I l I Q 3 L49 l J 7. I a 12 PAIENTEUUBI ems SHEET 3 0F 4 ELEVATOR-CONVEYOR FOR BULK MATERIAL This invention is directed to elevator conveyors and an object of the invention is to provide an elevatorconveyor which can carry bulk material, in particular granular and powderous material, along paths of any desired length and inclination, including vertical and horizontal paths and any combination of paths of different inclinations and, where the path is not horizontal, at will either upwards or downwards. The elevatorconveyor according to the invention, which will be referred to herein as conveyor for short, is intended to replace conventional mechanical elevators such as belt or chain (drag) conveyors, as well as conventional installations in which elevators and conveyors are combined since the former cannot operate in horizontal or slightly inclined stretches, and the conveyors cannot operate at inclinations beyond a certain angle.

The conveyor according to the invention belongs in principle to the field of mechanical elevator-conveyors which are as a rule preferred to pneumatic equipment since the latter is more expensive in terms of capital investment and operating and maintenance costs and requires longer interruptions of work for maintenance.

Among the known mechanical elevator-conveyors, bucket elevators are limited in speed because of the wear of their elements, susceptible to damage by foreign bodies and of heavy construction and weight. Chain conveyors are limited in speed and length, heavy and similarly susceptible to damage, and costly to operate and maintain. They may also cause damage to the material being conveyed. Belt conveyors are limited in inclination and open to wind and rain, and the material being conveyed is apt to be scattered and also to be contaminated.

The conveyor according to the invention eliminates the drawbacks of conventional elevator and conveyor equipment and provides advantages which will be set out below.

The invention contemplates a conveyor for bulk material, comprising two endless flexible belts; means for moving the two belts together, with the bulk material fully enclosed between them, along a working stretch extending between two different levels; means for applying fluid pressure to at least one of the belts along the said working stretch; means for feeding the bulk material between the two belts at a point before they enter the said working stretch, and means for allowing the bulk material to be discharged from the belts at a point after the latter leave the said working'stretch; and meansfor guiding the belts along return stretches from the discharge point to the feeding point. 7

The fluid pressure both seals the belts around the material and clamps the material within the space between the belts so that the, material is virtually immobilized relative to the belts.

n the return stretch from the delivery point to the feed point the belts may run along separate paths for which the required pulleys will be provided, or together over at least part of the return stretch, but in any case they will be separated from each other at the feed and I delivery points by as much as is required for the loading and unloading of the material to be conveyed.

The pressure fluid may be a gas or a liquid. The use of air is preferred.

The belts may consist of any suitable pliable material such as, for example, rubber of plastic, reinforced or unreinforced, or textile fabric impregnated so as to be impervious to the pressure fluid. They may be so designed that they bulge more readily in the middle than at the edges, e.g., by the preferential arrangement of reinforcing threads or wires along the edges.

For being subjected to air pressure, each belt by itself may run along a pneumatic box whose one open side is closed by the belt. Or else, both belts may run together through a single pneumatic box. Yet another arrangement consists in guiding one belt along a guide member which prevents the belt from yielding to air pressure, and applying pressure to the second belt only in order to press it on to the former.

Where a liquid, e.g., water, is used as the pressure fluid, analogous means will be provided for the application of the pressure to the belts.

The conveyor may be vertical or have a uniform inclination, or it may include different sections, depending on the conditions of each particular place of use. For example, there may be a first sloping or vertical ascending section for raising the material to a higher level, then a substantially horizontal section for con 'veying the material onwards at the higher level, and this may be followed by yet another sloping or vertical section, either ascending or descending, as demanded by local conditions. It is a great advantage provided by the invention that at the points of change of inclination, no transfer stations are required, as they generally must be in conventional equipment. The two belts simply continue on their way, withthe material enclosed between them, or one of the belts continues with the material, and the change of inclination merely requires the provision of appropriate direction-changing pulleys. There is virtually no limitation to the heightand length of the working stretch and the adjoining sections.

The conveyor according to the invention can be used for many different purposes. For example, it can be designed for the unloading of bulk material from ships or land vehicles and lifting the material, for example, to a silo. Or conversely, it may be used for loading ships with a controlled downward speed of the material, that is, the material descends at the same speed as do the conveyor belts, instead of falling freely or sliding down along a chute. V

The conveyor according to the invention is of particular advantage for the handling of granular and powderous materials such as grain, fertilizers and the like, but it can also be used for handling coarser materials such as coal, ores or the like. The width of the belt will be chosen in accordance with the'intended rate of conveyance (volume per unit of time for a given speed of the belts).

The fluid pressure must be great enough to create forces greater than the outwardly acting components of the column of material enclosed between the belts. It follows that the fluid pressure must be the stronger, the steeper the working stretch.

The two belts run at equal speeds and it will as a rule be sufficient to drive one of them while the second one is taken along by the first one on to which it is clamped by the fluid pressure.

The invention is illustrated, by way of example only, in the accompanying drawings in which:

FIG. 1 is a fragmentary schematic elevation, partly in vertical section, of a conveyor according to a first embodiment of the invention;

FIGS. 2A and 2B are cross-sections on line II-II of FIG. 1, showing the conveyor empty and loaded, respectively;

FIG. 3 is a section on line IIIIII of FIG. 1;

FIG. 4 is a section on line IV-IV of FIG. 1;

FIGS. 5 and 6 are fragmentary sections analogous to FIG. 4, of two modifications;

FIG. 7 is a fragmentary schematic elevation, partly in vertical section, of a conveyor according to a second embodiment of the invention;

FIG. 8 is a section on line VIIIVIII of FIG. 7;

FIG. 9 is a section on line IXIX of and FIGS. 10 and 11 are fragmentary schematic elevations of two conveyors according to the invention designed for the downward conveyance of bulk material.

The conveyor according to the invention shown in FIGS. 1 to 4 comprises two belts l, 2. These are running together upwards in a vertical working stretch between pulleys 3 and 4, and along a horizontal conveying stretch between the pulley 4 and a further pulley 5 (which may be the drive pulley). After passing the latter they separate for their return stretches on which the belt 1 is guided by idling pulleys 6, 7 and 8, and the belt 2 by idling pulleys 9, 10.

Over the height of the vertical working stretch there extend two upright pneumatic boxes 11, 12. They are closed on all sides except those which are turned towards the belt, so that the box 11 opens on to the back of belt 2, and the box 12 on to the bake of the belt 1.

The joints between the free edges of each box and the respective belt are sealed in any suitable known manner, e.g., by means of resilient gaskets 13 which are clamped between outward turned rims or lips 14 of the boxes (FIG. 2). The boxes are held together by means of frames 15.

, The boxes ll, 12 are supplied with pressurized air through the conduits l6, 17, respectively, which are connected to a source of pressurized air (not shown), e.g., a wind box or a blower.

The feed point is ahead of the junction of belts 1 and 2 at the pulley 3. A feed chute or hopper 18 is so disposed as to load the material to be conveyed on the belt 1 before the belt 2 joins the latter.

In the stretch between the pulley 8 and the hopper 18 the belt 1 assumes the shape of a trough. The material 19 to be conveyed is delivered into the deeper middle zone of this trough while the elevated edges of the belt remain free, and the width of the hopper l8 corresponds substantially to that of the middle zone of the belt (FIG. 3). As the belt thus loaded passes on to the pulley 3 the belt 2 covers the belt 1 and the material on the latter. If desired, the belts may be reinforced at the edges and be left more yielding in the middle.

In one embodiment of this conveyor, shown in FIG. 4, the pulley 3 has its middle profiled with an annular concavity which receives the bulging middle portion of the belt 2 while the free edges of the belts lie flat on the cylindrical parts of the pulley 3.

This conveyor operates as follows: the two belts run continually and at equal speeds in the directions indicated by the arrows, i.e., the stretches of both belts within the boxes 11, 12 run upwards, then, on top of the pulley 4, the belts, still together, pass through a horizontal stretch until they reach the pulley 5. There they separate and return each by itself, first horizontally, then downwards, until they meet again after the belt 1 has passed the hopper 18. This hopper continually discharges the material on to the belt 1, and after having passed the hopper and received the charge of material, the belt 1 is covered by the belt. 2. The two belts now enclose between them the material and, in this state, pass around the pulley 3. The outer belt, i.e., belt 1, enters at once into the box 12, and slightly later the belt 2 enters the box 11. In both boxes a state of superat mospheric pressure is continually maintained by the introduction of pressurized gas, usually air, through the conduits 16, 17. The magnitude of the required pressure depends on several parameters, of which the most important are the height of the vertical stretch of the conveyor, the nature of the material to be conveyed, and the cross-section of the column of material between the belts. It will have to be determined for each set of conditions. In a general manner, in the case of elevating grain, the pressure should be of the order of to 500 millimeters of water above atmospheric pressure.

In the horizontal stretch between pulleys 4 and 5 the belts still enclose between them the material but they are no longer under pneumatic pressure, which is no longer required. After passing the pulley 5, when the belts separate, the belt 1 discharges the material into a chute 20.

FIG. 1 shows in principle that the conveyor belts can change direction at any point and in any direction. The height of the ascending vertical stretch is not limited by inherent constructional features of the conveyor and can be determined by the needs of each particular case. The ascending stretch does not have to be vertical but may be inclined at any desired angle. The conveying stretch between pulleys 4 and 5, which, in this embodiment is horizontal, may be as long as required by particular conditions, and it may slop upwards or downwards. The conveyor need not end at the pulley 5 as shown here, but it may continue further with any desired inclination, either upwards or downwards.

In the modified embodiment shown in FIG. 5, the profiled pulley 3 of FIG. 4 has been replaced by a plain cylindrical steel pulley 3a. The belt 2 is applied flat against the pulley while the belt 1 bulges outwardly into the box 12. When the belts leave the pulley, the belt 2 also assumes the bulged shape so that the two belts together have the profile shown in FIG. 2B.

In another modification, shown in FIG. 6, the pulley 3bhas again a plain cylindrical shape and is of a hard material, e.g., steel, but its central part is recessed and has a lining 21 of a resilient material, e.g., rubber.

The conveyor illustrated in FIGS. 7-9 comprises one single pneumatic box 22 instead of the two boxes 11, 12 of the conveyor of FIG. 1. Within the single box 22 the two belts 1, 2, with the load 19 between them, are held together by the pneumatic pressure, and no gaskets (corresponding to the gaskets 13 of FIGS. 2A and 2B) are required at the edges of the belts. The pulleys 3 and 4 at the bottom and top ends of the vertical working stretch have the design of the pulley 3b of FIG. 6, i.e., they are steel cylinders with a recess filled with a resilient lining 21. The box 22 is sealed at it bottom and top ends as follows: at the bottom a resilient roller 23 bears against the belts in the region of pulley 3, and a steel roller 24 presses against the roller 23. The wall at the bottom end of the box 22 comes down very close to the roller 24. At the opposite side of the box.22, a roller 23a bears against the pulley 3, and a roller 24a against the roller 23a. At the top end of the box 22 the pressure through the the joints between the sealing rollers and the box are minimized.

The return stretch of belt 2 runs over pulleys 9' and 14. The return stretch of the belt 1 has not been shown in full, and the hopper for loading has not been shown either. The load 19 has been shown on both open horizontal stretches of the belt at the bottom and at the top of the conveyor.

A conveyor of this kind can be designed at will for either upward (unloading) or downward (loading) operation. For unloading operation, the feed hopper is located at the lower open stretch of belt 1, the two belts run upwards within the box 22, and the upper open stretch of belt 1 leads to a discharge point. For loading operation, the feed hopper is located at the upper open stretch of belt 1, the lower part of belt 1 leads to the discharge point, and the belts run downwardly within the box 22.

A similar reversal of function, i.e., downward operation instead of upward operation, can of course be effected in an analogous manner with the conveyor according to FIG. 1.

FIGS. 10 and 11 show in a general and schematic manner two designs of a conveyor according to FIG. 1 for loading, i.e., downward operation. 0n the upper open stretch of belt 1 a feed hopper 18 has been disposed, and this stretch of belt 1 has a moderate upward inclination towards the pulley 4. The conveyor according to FIG. 10 has no open bottom stretch of belt 1. The two belts separate at once upon leaving the bottom ends of the boxes 11, 12 and discharge the material straight downwards. According to FIG. 11 the material travels onwards in an open bottom stretch la of the belt 1 and is discharged at the end of that stretch.

What is claimed is:

l. A conveyor for transporting bulk material, comprising: 1

a. a pair of flexible fluid impermeable continuous belts each of which has a front surface and a rear surface; I

b. means mounting said belts so that the front surfaces of the belts face each other along a working stretch;

c. drive means for moving said belts at the same speed;

d. means for feeding bulk material between the front surfaces of said belts 'at a point before they enter said working stretch;

e. pressure means to apply fluid under pressure directly to the back surface of at least one of the belts along said working stretch for urging the front surfaces of said belts toward each other; and

f. the belts and the pressure means being constructed and arranged so that, along the working stretch, only the fluid pressure causes the middle portion of the front surface of each belt to be pressed into frictional engagement with said bulk material, and the opposite edge portions of the front surface of each belt on each side of the middle portion thereof to be pressed against each other into frictional gripping relationship whereby said bulk material is fully enclosed between said belts and is transported thereby.

2. A conveyor according to claim 1 wherein said pressure means comprises a pneumatic box associated with one of said belts, said box extending the length of said working stretch and including seal means that engage the respective edges of said one belt on the back surface thereof.

3. A conveyor according to claim 1 wherein said I pressure means is constructed and arranged to apply directly to the backs of both of said belts.

4. A conveyor according to claim 3 wherein said pressure means comprises a pair of pneumatic boxes respectively associated with said belts and extending substantially the length of said working stretch, each of said boxes including seal means engaged with opposite edges of the back surface of the belt with which the box is associated.

5. A conveyor according to claim 3 wherein said pressure means comprises a single pneumatic box establishing said working stretch and through which both said belts pass.

6. A conveyor according to claim 5 including a guide pulley at each end of said box, one guide pulley being engaged with the back surface of one of said belts and the other guide pulley being engaged with the back surface of the other of said belts, and including a pair of seal means at each end of said chamber, one of said seal means of each pair being resiliently engaged with a guide pulley and the other one of said seal means of each pair being engaged with the back surface of that belt which is not engaged with the last mentioned pulley.

7. A conveyor according to claim 1 including a guide pulley engaged with the back surface of one of said belts and having a central annular concavity for receiving the middle portion of said one belt, and said pulley having cylindrical edges for receiving the edge portions of said one belt.

8. A conveyor according to claim 1 including a guide pulley engaged with the back surface of one of said belts and having a cylindrical shape.

9. A conveyor according to claim 8 wherein said guide pulley has a resilient portion at least on the central peripheral region thereof for effecting the seating of the central portion of the belt.

10. A conveyor according to claim 1 including discharge means associated with the belts and located at a point where the belts leave said working stretch.

11. A conveyor according to claim 10 whereinsaid working stretch extends between two different levels, and said means for feeding the bulk material-to the conveyor are located substantially at the lower level of the conveyor, and the conveyor is designed to discharge the material substantially at the higher levelthereof.

12. A conveyor according to claim 10 wherein said working stretch extends between two different levels, and said means for feeding the bulk material to the conveyor are located substantially at the higher level of the conveyor, and the conveyor is designed to discharge the material substantially at the lower level thereof.

l3.'A conveyor according to claim 10 wherein said working stretch is substantially vertical.

14. A conveyor according to claim 10 wherein said working stretch is inclined.

15. A conveyor for transporting bulk material, comprising:

a. a pair of flexible continuous belts each of which has a front surface and a rear surface;

urging the front surfaces of the belts toward each other and causing the front surfaces of the middle portions of the belts to grip the bulk material and the opposite edge portions of the from surfaces of each belt on each side of the middle portion thereof to be pressed against each other into frictional gripping relationship whereby the bulk material is fully enclosed between the belts and is transported thereby. 

1. A conveyor for transporting bulk material, comprising: a. a pair of flexible fluid impermeable continuous belts each of which has a front surface and a rear surface; b. means mounting said belts so that the front surfaces of the belts face each other along a working stretch; c. drive means for moving said belts at the same speed; d. means for feeding bulk material between the front surfaces of said belts at a point before they enter said working stretch; e. pressure means to apply fluid under pressure directly to the back surface of at least one of the belts along said working stretch for urging the front surfaces of said belts toward each other; and f. the belts and the pressure means being constructed and arranged so that, along the working stretch, only the fluid pressure causes the middle portion of the front surface of each belt to be pressed into frictional engagement with said bulk material, and the opposite edge portions of the front surface of each belt on each side of the middle portion thereof to be pressed against each other into frictional gripping relationship whereby said bulk material is fully enclosed between said belts and is transported thereby.
 2. A conveyor according to claim 1 wherein said pressure means comprises a pneumatic box associated with one of said belts, said box extending the length of said working stretch and including seal means that engage the respective edges of said one belt on the back surface thereof.
 3. A conveyor according to claim 1 wherein said pressure means is constructed and arranged to apply directly to the backs of both of said belts.
 4. A conveyor according to claim 3 wherein said pressure means comprises a pair of pneumatic boxes respectively associated with said belts and extending substantially the length of said working stretch, each of said boxes including seal means engaged with opposite edges of the back surface of the belt with which the box is associated.
 5. A conveyor according to claim 3 wherein said pressure means comprises a single pneumatic box establishing said working stretch and through which both said belts pass.
 6. A conveyor according to claim 5 including a guide pulley at each end of said box, one guide pulley being engaged with the back surface of one of said belts and the other guide pulley being engaged with the back surface of the other of said belts, and including a pair of seal means at each end of said chamber, one of said seal means of each pair being resiliently engaged with a guide pulley and the other one of said seal means of each pair being engaged with the back surface of that belt which is not engaged with the last mentioned pulley.
 7. A conveyor according to claim 1 including a guide pulley engaged with the back surface of one of said belts and having a central annular concavity for receiving the middle portion of said one belt, and said pulley having cylindrical edges for receiving the edge portions of said one belt.
 8. A conveyor according to claim 1 including a guide pulley engaged with the back surface of one of said belts and having a cylindrical shape.
 9. A conveyor accoRding to claim 8 wherein said guide pulley has a resilient portion at least on the central peripheral region thereof for effecting the seating of the central portion of the belt.
 10. A conveyor according to claim 1 including discharge means associated with the belts and located at a point where the belts leave said working stretch.
 11. A conveyor according to claim 10 wherein said working stretch extends between two different levels, and said means for feeding the bulk material to the conveyor are located substantially at the lower level of the conveyor, and the conveyor is designed to discharge the material substantially at the higher level thereof.
 12. A conveyor according to claim 10 wherein said working stretch extends between two different levels, and said means for feeding the bulk material to the conveyor are located substantially at the higher level of the conveyor, and the conveyor is designed to discharge the material substantially at the lower level thereof.
 13. A conveyor according to claim 10 wherein said working stretch is substantially vertical.
 14. A conveyor according to claim 10 wherein said working stretch is inclined.
 15. A conveyor for transporting bulk material, comprising: a. a pair of flexible continuous belts each of which has a front surface and a rear surface; b. means mounting said belts so that the front surfaces of the belts face each other along a working stretch; c. drive means for moving said belts at the same speed; d. means for feeding bulk material between the front surfaces of said belts at a point before they enter said working stretch; e. a single pneumatic box extending the length of the working stretch and through which the belts pass; f. means to apply fluid under pressure to the box for urging the front surfaces of the belts toward each other and causing the front surfaces of the middle portions of the belts to grip the bulk material and the opposite edge portions of the front surfaces of each belt on each side of the middle portion thereof to be pressed against each other into frictional gripping relationship whereby the bulk material is fully enclosed between the belts and is transported thereby. 